1. Field of the Invention
The present invention relates generally to database retrieval systems for storing drawing information, and more particularly to a drawing information presentation apparatus and method in a database retrieval system for effectively displaying differences between elements of plural drawings.
2. Description of the Background
Recently, a database retrieval system has been constructed to store a large amount of patent information in its database. The patent information consists of the drawings contained in patents, wherein each patent has previously assigned plural keywords which indicate characteristics of the disclosure of the patent. A user of the system desires to retrieve patents which are most similar to an input description or drawing. To use the system, the user inputs a keyword which indicates characteristics of the input data. Then, the database retrieval system retrieves patent information consisting of those patents whose keywords coincide with input keyword, and displays the retrieved patent information.
In general, such database retrieval system is useful to determine whether patents exist or not. For example, when a new product is developed in a company, the development engineer must determine whether the product may be described in a patent which has already issued. If such patent has already issued, the engineer must determine differences between elements of the new product and the patent. For the purpose of this patent search, the database retrieval system is used.
In this case, stored patent information and input data includes plural drawings. Specifically, the patent information includes a block diagram corresponding to a claim. Such block diagram is called a "claim correspondence drawing". In addition, a block diagram of the new product is also previously stored in the database retrieval system. Firstly, the engineer inputs a keyword which indicates characteristics of the new product. The database retrieval system retrieves patent information whose keyword coincides with input keyword and displays the retrieval patent information, including the claim correspondence drawing. Then the engineer makes the database retrieval system display the claim correspondence drawing and the block diagram of the new product, to permit comparison between the drawing and the diagram.
It often happens, however, that technical labels for similar function blocks, and the block arrangement and location are different between these two drawings. For example, FIG. 1 shows a block diagram of new CPU for artificial intelligence (AI) and FIG. 2 shows a block diagram of a CPU for a reduced instruction set computer (RISC). It is assumed that FIG. 1 is block diagram of new product and FIG. 2 is claim correspondence drawing of patent information from a data base. Though both these two diagrams show CPUs, the element arrangement and location is different between these two drawings. Moreover, even if two elements are substantially same (for example, "instruction cache control" in FIG. 1 and "instruction cache" in FIG. 2), the characters providing text description of these technical terms are different. Therefore, when the user views these two drawings on a display to compare them, it takes a long time for the user to discriminate the similarities and differences between these two drawings.
Thus, in the prior art, when user desires to compare drawings stored in database, the prior art database retrieval system only displays these drawings. In short, the database retrieval system cannot effectively present the difference between two drawings on display to user.